The invention disclosed herein relates generally to method of combining metals. More specifically, this invention relates to a method of combining metals with different melting points.
Induction melting is the technique of melting materials that are electrical conductors by establishing electrical current in these materials. The current is induced by a changing magnetic flux created by the passage of current in the radio frequency range through a set of induction coils that surround the material. An alternating current in the induction coils results in a changing magnetic flux. The changing magnetic flux results in an induced current in tie material. Flow of current in a conductor will result in joule heating that raises the temperature of the material. Note that the objects being heated need not be a magnetic material to heat efficiently. All that is required is that it have reasonably good electrical conductivity. Most ferrous and nonferrous metals can be heated and melted inductively. Induction melting furnaces use the principle of induction melting. A typical induction furnace comprises a single melting crucible that is surrounded by an induction coil connected to a source of alternating current.
A vacuum induction furnace having a single melting crucible may be used, in certain circumstances, to melt two different metals together in the furnace""s single crucible even though there are substantial differences between the melting points of the two metals. For example, 100% magnesium (Mg) has a melting point of about 650xc2x0 C. and 100% nickel (Ni) has a melting point of around 1453xc2x0 C. However, Mg and Ni can form the intermetallic compound Mg2Ni that has a melting point of about 760xc2x0 C. Hence, Mg and Ni can be melted in the same crucible at the 760xc2x0 C. melting point of Mg2Ni. At this temperature, there would not be substantial vaporization of magnesium.
In contrast, magnesium and iron cannot easily be melted in the same crucible. Unlike the Mg-Ni system described above, magnesium and iron is not known to form an intermetallic compound. Hence, to melt magnesium and iron in the same crucible, the crucible would have to be heated above the 1535xc2x0 C. melting point of iron. At this temperature, there would be substantial magnesium vaporization. Hence, there is a need for a new method to combine metals having different melting points and especially metals lacking intermetallic compounds.
One objective of the present invention is to provide a method of combining a first metal with a second metal where the melting points of the first metal and the second metal are different.
This and other objectives are satisfied by a method for combining a first metal with a second metal, said method comprising the steps of: providing the first metal and the second metal were the melting point of the second metal is greater than the melting point of the first metal; melting the first metal in a first melting crucible to produce a first molten metal; melting the second metal in a second melting crucible to produce a second molten metal; and introducing the second molten metal onto or into the first molten metal.